1. Field of the Invention
The present invention relates to the field of data transfer. More particularly, the present invention relates to improving latency of one or more agents operating in accordance with a round robin arbitration scheme.
2. Description of Art Related to the Invention
For many years, electronic systems (e.g., networks, computer systems, printers, etc.) have been designed to allow multiple agents exclusive access to a single resource such as an interconnect bus, memory and the like. These agents, normally hardware devices, issue resource requests to gain exclusive access to the resource for at most a predetermined period of time. Typically, an arbitration circuit is required to arbitrate access to the resource between multiple "requesting agents" (i.e., agents simultaneously requesting access to the resource). After one of the requesting agents gains access to the resource, it performs a particular operation and relinquishes access to the resource upon completion of the particular operation or expiration of the predetermined time period, whichever occurs first.
At the moment, there exists a number of well-known arbitration schemes used by arbitration circuits. One arbitration scheme is called "fixed priority arbitration" which grants access of the resource to a requesting agent having the highest priority. Thus, this highest priority agent is guaranteed to experience very low latency. However, the fixed priority arbitration scheme "starves" requesting agents assigned with a low priority when an agent assigned with the highest priority is frequently requesting access to the resource.
Another arbitration scheme is called "round robin arbitration" which is slightly more complex to implement than fixed priority arbitration. However, it offers the advantage of uniform resource allocation. As a result, the latency imposed on the requesting agents is generally uniform since each requesting agent is provided access to the resource before another agent regains access to the resource. Generally, this type of arbitration is preferred except when at least one of the agents, referred to as a "latency sensitive agent", must comply with strict latency constraints. In that case, the use of round robin arbitration would expose the electronic system to performance degradation and perhaps catastrophic data loss if the delay caused by the other agents in the electronic system accessing the resource exceeds the latency constraints imposed on the latency sensitive agent.
Hence, it would be desirable to implement an arbitration circuit operating in accordance with a round robin arbitration scheme which is specifically configured to minimize latency experienced by one or more agents which are subject to strict latency requirements.